This invention relates to a display device which comprises a display unit that can alternately display two kinds of contents to be displayed by means of a flap operative to rotate in opposite directions by the action of a magnet.
Heretofore, it has been well known to provide a display unit that can selectively display either one of two kinds of displays by means of a flap provided with a magnet and rotable between two positions by changing over the polarity of an electromagnet opposed to the magnet of the flap and by rotating the flap from one position to the other position. In addition, a novel display device has been developed in which a plurality of display units are combined into one block and all of flaps are simultaneously rotated in an opposite direction so as to change over the contents displayed, or only those flaps which belong to any desired display unit are rotated in opposite directions so as to display the desired pattern.
However, these well known display devices have the disadvantage that provision must be made of both a memory device and a switch mechanism which are complex in construction in order to select a display unit to be rotated in an opposite direction in response to change of contents to be displayed and to reverse the polarity of an electromagnet of the display unit thus selected.